Our long-term goal is to evaluate the effect of pegylated interferon (peg-IFN) ? as an anti-HIV reservoir immunotherapy that could potentiate eradication strategies against HIV. The short-term goal of this proposal is to conduct a randomized clinical trial (RCT) to determine whether a 20-week treatment course with peg-IFN-?2b 1ug/kg/week, with or without a 4-week ART interruption, will reduce HIV-1 proviral DNA levels in circulating PBMC and gut mucosa-associated lymphoid tissue (MALT) in ART- treated long-term viral suppressed subjects with immune reconstitution. In our recently completed clinical trial (NCT00594880), we demonstrated that treatment with peg-IFN-?2a started on ART resulted in 12 week viral suppression during ART interruption (peg-IFN-?2a monotherapy) in 50% of the subjects, concurrently with activation of intrinsic anti-HIV genes, higher NK responses, and a significant reduction in integrated proviral HIV DNA (a measure of latent reservoir). In order to reproduce our findings, determine the requirement for viral reactivation to trigger anti-HIV responses, and gather insights into mechanism of action, we propose to conduct a randomized clinical trial (RCT) to test our primary hypothesis that 20 weeks of treatment with peg-IFN-?2b (with or without HIV reactivation following ART interruption) will activate intrinsic and immune-mediated anti-HIV responses resulting in a reduction of integrated HIV DNA in chronically HIV-infected, immune-reconstituted individuals when compared to a control group of individuals undergoing comparable ART treatment in the absence of peg-IFN-?2b. We propose to test this hypothesis by addressing the following specific aims: Specific Aim 1: to assess the effectiveness of a 20-week course of peg-IFN-?2b to reduce measures of HIV reservoir by conducting an RCT to a) compare the change in integrated proviral HIV DNA/peripheral blood CD4+ T cell in ART suppressed subjects receiving peg-IFN-?2b treatment to an expected change of zero in the control group (primary endpoint); b) assess the requirement for viral replication (via short-term ART interruption) to activate immune mechanisms leading to the reduction of integrated HIV DNA; c) compare total and integrated HIV DNA levels in MALT-associated CD4+ T lymphocytes from rectal mucosal biopsies; d) compare levels of integrated DNA to other measures of viral reservoir (Q-VOA, ddPCR). Specific Aim 2: to characterize the anti-HIV intrinsic (host gene expression), innate and CD8 T-cell responses underlying changes in integrated HIV DNA following peg-IFN-?2b immunotherapy, as well as their correlation with secondary viral measures (ddPCR or Q-VOA).